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Saint-André-lez-Lille, France

Certad G.,French Institute of Health and Medical Research | Dupouy-Camet J.,University of Paris Descartes | Gantois N.,French Institute of Health and Medical Research | Hammouma-Ghelboun O.,Institute Superieur Dagriculture Of Lille | And 15 more authors.
PLoS ONE | Year: 2015

Cryptosporidium, a protozoan parasite that can cause severe diarrhea in a wide range of vertebrates including humans, is increasingly recognized as a parasite of a diverse range of wildlife species. However, little data are available regarding the identification of Cryptosporidium species and genotypes in wild aquatic environments, and more particularly in edible freshwater fish. To evaluate the prevalence of Cryptosporidiumspp. in fish from Lake Geneva (Lac Léman) in France, 41 entire fish and 100 fillets (cuts of fish flesh) were collected from fishery suppliers around the lake. Nested PCR using degenerate primers followed by sequence analysis was used. Five fish species were identified as potential hosts of Cryptosporidium: Salvelinus alpinus, Esox lucius, Coregonus lavaretus, Perca fluviatilis, and Rutilus rutilus. The presence of Cryptosporidium spp. was found in 15 out of 41 fish (37%), distributed as follows: 13 (87%) C. parvum, 1 (7%) C. molnari, and 1 (7%) mixed infection (C. parvum and C. molnari). C. molnari was identified in the stomach, while C. parvum was found in the stomach and intestine. C. molnari was also detected in 1 out of 100 analyzed fillets. In order to identify Cryptosporidium subtypes, sequencing of the highly polymorphic 60-kDa glycoprotein (gp60) was performed. Among the C. parvum positive samples, three gp60 subtypes were identified: IIaA15G2R1, IIaA16G2R1, and IIaA17G2R1. Histological examination confirmed the presence of potential developmental stages of C. parvum within digestive epithelial cells. These observations suggest that C. parvum is infecting fish, rather than being passively carried. Since C. parvum is a zoonotic species, fish potentially contaminated by the same subtypes found in terrestrial mammals would be an additional source of infection for humans and animals, and may also contribute to the contamination of the environment with this parasite. Moreover, the risk of human transmission is strengthened by the observation of edible fillet contamination. © 2015 Certad et al.

Sabra N.,Lebanese University | Dubourguier H.-C.,Institute Superieur Dagriculture Of Lille | Duval M.-N.,Institute Superieur Dagriculture Of Lille | Hamieh T.,Lebanese University
Environmental Technology | Year: 2011

Filamentous fungi and lithotrophic bacteria were used to leach heavy metals from dredged sediments in semi-pilot scale air-lift bioreactors. A preliminary physico-chemical characterization of the sediments comprising a sequential extraction study revealed their high metallic contamination and a predominant association of the metals with sulphides and organic matter. The mobility of heavy metals from sediments was ranked by decreasing order as follows: Mn Zn Cd Cu Pb. The conditions that favoured the solubilization of heavy metals by filamentous fungi turned out to be also favourable for the activity of the sediment organotrophic bacteria. The latter produced organic acids under temporary hypoxic conditions and resulted in the solubilization of 77% of manganese, 44% of zinc, 12% of copper, and less than 2% of cadmium or lead. In general, the fungal organotrophic treatments were limited to the relatively mobile metals due to the weak nature of the organic acids produced and to their microbial consumption under limited saccharose conditions. The lithotrophic treatments yielded higher solubilization results than the organotrophic experiments. Sulphur resulted in a faster, and for some metals such as copper and cadmium, in better bioleaching results compared with reduced iron or with a combination of reduced iron and sulphur. The bioleaching percentages varied between 72 and 93% for cadmium, copper, manganese and zinc, except for lead because of the poor solubility of lead sulphate. The sediment's lithotrophic bacteria acidified the matrix through sulphur oxidation, and leached both loosely and tightly bound metals. © 2011 Taylor & Francis.

Sabra N.Y.,Lebanese University | Dubourguier H.C.,Institute Superieur Dagriculture Of Lille | Benmimouna A.,Institute Superieur Dagriculture Of Lille | Duval M.N.,Institute Superieur Dagriculture Of Lille | And 2 more authors.
Open Environmental Sciences | Year: 2011

Lithotrophic bacterial leaching of heavy metals from dredged sediments was studied in semi-pilot scale air-lift bioreactors. Prior to the bioleaching experiments, a physico-chemical characterization of the sediments comprising a sequential extraction study was conducted. The sediments turned out to be highly loaded with heavy metals, and with the exception of managanese, mainly associated to the oxidizable fraction of the sediments and thus strongly linked to the latter. The heavy metals could be classified by decreasing order of mobility as follows: Mn>Zn>Cu>Cd>Pb. The bacterial leaching was found to be strongly dependent on the nature of the mineral substrate. Sulfur gave the best solubilization results in comparison with reduced iron or with a combination of reduced iron and sulfur. In the presence of oxygen, lithotrophic bacteria oxidized sulfur into sulfates and induced an acidification of the sediments. These conditions led to the release of the metals that were tightly linked to the sediments, that is those associated with the sulfides and/or with the organic matter. With sulfur as a substrate, the solubilization percentages varied within 30 days between 72 and 93% of the total sediment content (wt/wt) for cadmium, copper, manganese and zinc. Much lower biosolubilization percentages were obtained in the case of lead because of the poor solubility of lead sulfate. © Sabra et al.

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